- FILESIZE - total file size in an auto-rounded value with suffix (B/K/M/G)
- FILEBYTES - total file size in bytes
- FILEKB - total file size in kibibytes
- FILEMB - total file size in mebibytes
- FILEGB - total file size in gibibytes

All of the above default to the current file transfer directory path from where
to find / calculate the sizes of files. Only files that exist in the actual
storage directory are counted (offline files or file in alt. file paths are not
counted).

All of the above support 2 alternate syntaxes:

FILE*:<dir-code> where <dir-code> is the internal code of a file directory, or
FILE*:<path[/file-spec]> where <path> is a directory path and [/file-spec] is
an optinal file name/specification (i.e. w/wildcards).